That's the problem, you're just looking at specs.

Look at a Geforce 680M, it's not a Desktop Geforce 680 in any sense of the word, more like a Geforce 660Ti with bugger-all bandwidth and lower clock speeds, so it would probably perform more like a vanilla Geforce 660 in memory-bandwidth hungry games.

The Radeon 7970M? Is more or less a Desktop Radeon 7870, but clocked lower.

Surely you can build a Desktop that matches that for cheaper. ;)

Then when the time comes to upgrade, you throw the whole laptop out instead of just a little overclocking and a new GPU, costing you more in the long run.
Not to mention SCREENS, most laptops are only running with 1920x1080 resolution screens (Or lower!) and they are usually crappy TN panels instead of IPS.

Keep in mind, while Alineware laptops don't seem to be popular in this thread, there are GPU upgrade kits that would later allow you to keep your laptop up-to-date.

HD7970M for Alienware

http://www.ebay.com/itm/HD7970M-Alienware-M17x-M18x-VGA-Upgrade-Kit-Dell-OEM-HD7970M-2GB-DDR5-CF-Ready-/121041654791?pt=PCC_Video_TV_Cards&hash=item1c2ea51407

GTX680M for Alienware

http://www.ebay.com/itm/NEW-Dell-Alienware-Nvidia-GTX-680m-Video-Card-MXM-3-0b-for-MXM-Laptop-M17x-M18x-/181058512456?pt=PCC_Video_TV_Cards&hash=item2a27eda648

That means in 2-3 years you won't have to toss the laptop out. I am not sure what GPU upgrade options are available for the other high-end gaming laptops but I notice that GPU upgrades for Alineware laptops are not too hard to find on eBay. 

As others have mentioned though Alienware laptops are often overpriced in terms of components and their actual case seems outdated:

http://www.anandtech.com/show/6336/alienware-m18x-r2-notebook-review-nvidias-geforce-gtx-680m-in-sli

It really comes down to how much you want to spend. There are gaming laptops that cost less and are still decent:

http://hothardware.com/Reviews/iBuyPowers-CZ17-Review-of-the-Valkyrie/

Because the naming schemes of mobile GPUs are extremely convoluted, it's best to refer to actual benchmarks/chart that compiles them:

http://www.notebookcheck.net/Mobile-Graphics-Cards-Benchmark-List.844.0.html

Nvidia prices their GPUs much higher than equivalent AMD cards in performance. For example, Nvidia actually charges more $ for a GTX675M but it's MUCH slower than HD7970M:

http://configure.us.dell.com/dellstore/config.aspx?oc=dkdwgy1&model_id=alienware-m17x-r4&c=us&l=en&s=dhs&cs=19

So make sure to refer to the table at NotebookCheck.

Great post. You cannot compare GPU names between desktops and laptops and assume they are equivalent. Most PC gamers shy away from PC gaming laptops because of how insanely overpriced they are. The crazy part is you could build a small case LAN PC with a GTX680/GTX690 and get a Catleap 2560x1440 monitorand leave it at your friend's house for LAN than to get a powerful gaming laptop.

Or Lian Li PC-TU200B case with a GTX690 inside of it.

This case above still manages to fit a 30 cm videocard!

http://www.lian-li.com/v2/en/product/product06.php?pr_index=585&cl_index=1&sc_index=25&ss_index=64&g=f

Im not tech savy, I would just be wasting my time 

Then why do you argue with us, more tech savvy people?

Oh my fucking God, he^^ calls himself tech savy...

I'm no engineer, but I sure know how to build myself a gaming PC. 

This arguement over laptops versus PC is very simple for me. All in, my desktop cost me £1600, and that includes an i5, SSD and HDD combo and a GTX 670, oh and 2 screens. So firstly, you can't get the same screen real estate, secondly, you can't get anywhere near the gaming performance. On the price, you could easily spend over £2,000 on a gaming PC and it wouldn't match the performance of my desktop.

BUT, my PC is not going anywhere any time soon.

As for the OP, I don't know that much about gaming laptops, since I just accepted that you aren't going to get very good performance, but another thing to look into might be a small form PC

I know many have criticised Alienware, but I think this is a good example
http://www.dell.com/uk/p/alienware-x51/pd?oc=d00and49&model_id=alienware-x51

You could build one yourself, but I think a smaller PC will be harder work than making a larger one (which I had great fun doing). This would be good for LAN parties, if there is a screen you can borrow, but if you really do want portability, just know that you are paying more for less in terms of gaming

Can you build me one? I'll provide the money

If he builds you one, you'll never learn how to build one yourself!

All you need is this guide with videos:

http://techreport.com/review/23624/how-to-build-a-pc-the-tech-report-guide

and a separate thread like this one:

http://gamrconnect.vgchartz.com/thread.php?id=150851&page=1#

You'll get help in no time and actually learn how to put together a PC yourself saving you money over the lifetime (and teach your friends/family how to build their own PCs too. Steam money savings will follow later!) :)